三江平原农田排水期流域水体CH_(4)排放特征及影响因素  

Characteristics of methane(CH_(4))emissions and influencing factors in surface waters of farmland during the drainage period in the Sanjiang Plain

作　　者：刘凯明 张海 李霞[1,2] 王明国 杨涛 李军 白莉[1] 刘小龙[1] LIU Kai-ming;ZHANG Hai;LI Xia;WANG Ming-guo;YANG Tao;LI Jun;BAI Li;LIU Xiao-long(Tianjin Key Laboratory of Water Resources and Environment,Tianjin Normal University,Tianjin 300387,China;College of Geography and Environmental Science,Tianjin Normal University,Tianjin 300387,China;Center for Hydrogeology and Environmental Geology,China Geological Survey,Baoding 071051,China)

机构地区：[1]天津师范大学,天津市水资源与水环境重点实验室,天津300387 [2]天津师范大学,地理与环境科学学院,天津300387 [3]中国地质调查局,水文地质环境地质调查中心,河北保定071051

出　　处：《中国环境科学》2024年第6期3078-3090,共13页China Environmental Science

基　　金：中国地质调查局地质调查项目(DD20190534,DD20221754);天津市科技局项目(21ZYJDJC00090);国家自然科学基金资助项目(41672351,41661144029)。

摘　　要：在施肥和土壤淋溶等多种因素的影响下,农业流域水体甲烷(CH_(4))的源汇关系尚不明确,目前对于农业流域水体CH_(4)排放的监测和研究仍然不足.本研究选取三江平原的浓江流域为研究对象,利用顶空平衡法和扩散模型法对该流域不同水体的CH_(4)浓度和排放通量进行监测和估算.结果表明:浓江流域水体普遍为CH_(4)的排放源,鸭绿河、浓江河流、沟渠和稻田水体的CH_(4)排放通量范围分别为0.51~99.60、0.97~20.44、4.13~20.90和24.84~58.07mg/(m^(2)·d),且沟渠和稻田水体的CH_(4)排放通量较高,分别为浓江河流的2倍和7倍.在鸭绿河干流和沟渠水体中,CH_(4)浓度与pH值和溶解氧(DO)均呈显著负相关,浓江干流的CH_(4)浓度与DO呈显著正相关.浓江干流和沟渠水体的CH_(4)浓度与溶解性有机碳(DOC)呈显著正相关,表明排水期农业有机肥的使用会促进水体CH_(4)的产生.流经湿地浅水区和受农田施肥影响的河段水体具有较高的CH_(4)浓度和排放通量,表明CH_(4)排放受到了土地利用方式的显著影响.相比于全球其他农业河流,排水期浓江流域河水在排水期具有较高的CH_(4)浓度和较低的CH_(4)排放通量,较低风速缓解了水-气界面的排放.而沟渠水体排水期间较低的CH_(4)排放通量主要受富氧状态的影响.三江平原作为典型的东北黑土农业区,探究其农业流域CH_(4)的产生和排放对于未来区域的碳收支平衡和碳排放评估具有重要意义.Under the influences of fertilization and soil leaching,the source and sink effects of methane(CH_(4))in surface waters of agricultural watersheds remain unclear.Currently,the monitoring and studying of CH_(4)emissions in waters of agricultural watersheds are still inadequate.This study focused on the Nongjiang River Basin within the Sanjiang Plain,employing the headspace equilibrium method and the diffusion model approach to precisely monitor and estimate the CH_(4)concentrations and fluxes in various water bodies of the basin.The results showed that the water bodies in the Nongjiang watershed generally acted as sources of atmospheric CH_(4).The CH_(4)fluxes at the water-air interfaces of the YalüRiver,Nongjiang River,ditches,and paddy fields ranged from 0.51 to 99.60,0.97 to 20.44,4.13 to 20.90,and 24.84 to 58.07mg/(m^(2)⋅d),respectively.The CH_(4)fluxes from ditches and paddy fields were 2 and 7 times higher than those of the Nongjiang River,respectively.In the YalüRiver and ditches,CH_(4)concentrations correlated significantly and negatively with pH and dissolved oxygen(DO),while the CH_(4)concentrations in the Nongjiang River correlated significantly and positively with DO.The CH_(4)concentrations in the Nongjiang River and ditches water bodies were significantly positively correlated with dissolved organic carbon(DOC),indicating that the use of agricultural organic fertilizer during the drainage period promotes the production of CH_(4).The study found that river reaches that flow through shallow wetlands and agricultural areas generally have higher CH_(4)concentrations and fluxes,suggesting the effects of land use patterns on CH_(4)emissions were important.Compared with other agricultural watersheds globally,the Nongjiang River during the drainage period has higher CH_(4)concentrations and lower CH_(4)fluxes,low wind speed eased the CH_(4)diffusion at water-air interface;while the the low CH_(4)flux in the ditch waters during the drainage period mainly resulted from the high DO.As a typical agricultural

关 键 词：农业流域 排水期 温室气体CH_(4) 产生与排放 

分 类 号：X51[环境科学与工程—环境工程]